Add some more tests with views to test recursive planning on views (#4404)

src/test/regress/expected/subquery_view.out

@@ -3,6 +3,7 @@
 -- ===================================================================
 CREATE SCHEMA subquery_view;
 SET search_path TO subquery_view, public;
+SET citus.next_shard_id TO 1512000;
 CREATE TABLE users_table_local AS SELECT * FROM users_table;
 CREATE TABLE events_table_local AS SELECT * FROM events_table;
 SET client_min_messages TO DEBUG1;
@@ -560,8 +561,79 @@ DEBUG:  Plan XXX query after replacing subqueries and CTEs: SELECT user_id, user
 (5 rows)
 
 SET client_min_messages TO DEFAULT;
+CREATE TABLE reference_table (text_col text, int_col int);
+SELECT create_reference_table('reference_table');
+ create_reference_table
+---------------------------------------------------------------------
+
+(1 row)
+
+EXPLAIN (COSTS OFF) WITH cte AS (
+  SELECT application_name AS text_col
+  FROM pg_stat_activity
+) SELECT * FROM reference_table JOIN cte USING (text_col);
+                                            QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)
+   ->  Distributed Subplan XXX_1
+         ->  Function Scan on pg_stat_get_activity s
+   ->  Distributed Subplan XXX_2
+         ->  Custom Scan (Citus Adaptive)
+               Task Count: 1
+               Tasks Shown: All
+               ->  Task
+                     Node: host=localhost port=xxxxx dbname=regression
+                     ->  Hash Left Join
+                           Hash Cond: (intermediate_result.usesysid = u.oid)
+                           ->  Hash Left Join
+                                 Hash Cond: (intermediate_result.datid = d.oid)
+                                 ->  Function Scan on read_intermediate_result intermediate_result
+                                 ->  Hash
+                                       ->  Seq Scan on pg_database d
+                           ->  Hash
+                                 ->  Seq Scan on pg_authid u
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  Merge Join
+               Merge Cond: (intermediate_result.application_name = reference_table.text_col)
+               ->  Sort
+                     Sort Key: intermediate_result.application_name
+                     ->  Function Scan on read_intermediate_result intermediate_result
+               ->  Sort
+                     Sort Key: reference_table.text_col
+                     ->  Seq Scan on reference_table_1512000 reference_table
+(30 rows)
+
+CREATE OR REPLACE VIEW view_on_views AS SELECT pg_stat_activity.application_name, pg_locks.pid FROM pg_stat_activity, pg_locks;
+EXPLAIN (COSTS OFF) WITH cte AS (
+  SELECT application_name AS text_col
+  FROM view_on_views
+) SELECT * FROM reference_table JOIN cte USING (text_col);
+                                      QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)
+   ->  Distributed Subplan XXX_1
+         ->  Nested Loop
+               ->  Function Scan on pg_stat_get_activity s
+               ->  Function Scan on pg_lock_status l
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  Merge Join
+               Merge Cond: (intermediate_result.text_col = reference_table.text_col)
+               ->  Sort
+                     Sort Key: intermediate_result.text_col
+                     ->  Function Scan on read_intermediate_result intermediate_result
+               ->  Sort
+                     Sort Key: reference_table.text_col
+                     ->  Seq Scan on reference_table_1512000 reference_table
+(17 rows)
+
 DROP SCHEMA subquery_view CASCADE;
-NOTICE:  drop cascades to 17 other objects
+NOTICE:  drop cascades to 19 other objects
 DETAIL:  drop cascades to table users_table_local
 drop cascades to table events_table_local
 drop cascades to view view_without_subquery
@@ -579,4 +651,6 @@ drop cascades to view subquery_and_ctes
 drop cascades to view subquery_and_ctes_second
 drop cascades to view deep_subquery
 drop cascades to view result_of_view_is_also_recursively_planned
+drop cascades to table reference_table
+drop cascades to view view_on_views
 SET search_path TO public;

src/test/regress/sql/subquery_view.sql

@@ -5,6 +5,7 @@
 CREATE SCHEMA subquery_view;
 SET search_path TO subquery_view, public;
 
+SET citus.next_shard_id TO 1512000;
 
 CREATE TABLE users_table_local AS SELECT * FROM users_table;
 CREATE TABLE events_table_local AS SELECT * FROM events_table;
@@ -426,5 +427,20 @@ ORDER BY time DESC LIMIT 5;
 
 SET client_min_messages TO DEFAULT;
 
+CREATE TABLE reference_table (text_col text, int_col int);
+SELECT create_reference_table('reference_table');
+
+EXPLAIN (COSTS OFF) WITH cte AS (
+  SELECT application_name AS text_col
+  FROM pg_stat_activity
+) SELECT * FROM reference_table JOIN cte USING (text_col);
+
+CREATE OR REPLACE VIEW view_on_views AS SELECT pg_stat_activity.application_name, pg_locks.pid FROM pg_stat_activity, pg_locks;
+
+EXPLAIN (COSTS OFF) WITH cte AS (
+  SELECT application_name AS text_col
+  FROM view_on_views
+) SELECT * FROM reference_table JOIN cte USING (text_col);
+
 DROP SCHEMA subquery_view CASCADE;
 SET search_path TO public;